The purpose of the proposed research is to determine the organization of the functional anatomy of the central regulation of the anterior pituitary. Our research involves a topographical study of the location of releasing factor containing neuronal perikarya and the pathways by which their axons reach the median eminence. In addition, other studies are focused upon the quantitative investigation of dopaminergic, noradrenergic, cholinergic, and gabaminergic fiber inputs to the medial basal hypothalamus and interior hypothalamus. In addition, we are investigating the effects of changes in the endocrine milieu and the administration of neuroleptic drugs on the kinetic properties of tyrosine hydroxylase and on the rates of synthesis of catecholamine neurotransmitters. Other studies involve investigation of specific lesions of various neuronal inputs to the hypothalamus on central neuroendocrine regulation. Finally, we have begun investigations of the use of drugs which appear to be specifically cytotoxic for neuronal perikarya as tools for determining the origin of specific fiber inputs to the diencephalon of the rat.